Implement pwritev2.

Implement pwritev2 and associated unit tests.
Clean up preadv2 unit tests.
Tag RWF_ flags in both preadv2 and pwritev2 with associated bug tickets.

PiperOrigin-RevId: 226222119
Change-Id: Ieb22672418812894ba114bbc88e67f1dd50de620

9 files changed, 553 insertions, 73 deletions

diff --git a/pkg/abi/linux/file.go b/pkg/abi/linux/file.go
index ac49ae9a6..ae33f4a4d 100644
--- a/pkg/abi/linux/file.go
+++ b/pkg/abi/linux/file.go
@@ -152,9 +152,10 @@ const (
 
 // Values for preadv2/pwritev2.
 const (
-	RWF_HIPRI = 0x0001
-	RWF_DSYNC = 0X0002
-	RWF_SYNC  = 0x0004
+	RWF_HIPRI = 0x00000001
+	RWF_DSYNC = 0x00000002
+	RWF_SYNC  = 0x00000004
+	RWF_VALID = RWF_HIPRI | RWF_DSYNC | RWF_SYNC
 )
 
 // Stat represents struct stat.
diff --git a/pkg/sentry/syscalls/linux/linux64.go b/pkg/sentry/syscalls/linux/linux64.go
index cc5ebb955..e855590e6 100644
--- a/pkg/sentry/syscalls/linux/linux64.go
+++ b/pkg/sentry/syscalls/linux/linux64.go
@@ -377,7 +377,7 @@ var AMD64 = &kernel.SyscallTable{
 		// Syscalls after 325 are "backports" from versions of Linux after 4.4.
 		//	326: CopyFileRange,
 		327: Preadv2,
-		//	328: Pwritev2,  // Pwritev2, TODO
+		328: Pwritev2,
 	},
 
 	Emulate: map[usermem.Addr]uintptr{
diff --git a/pkg/sentry/syscalls/linux/sys_read.go b/pkg/sentry/syscalls/linux/sys_read.go
index cbb9eb9f8..b6df4d9d4 100644
--- a/pkg/sentry/syscalls/linux/sys_read.go
+++ b/pkg/sentry/syscalls/linux/sys_read.go
@@ -188,14 +188,20 @@ func Preadv(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal
 }
 
 // Preadv2 implements linux syscall preadv2(2).
+// TODO: Implement RWF_HIPRI functionality.
 func Preadv2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	// While the syscall is
+	// preadv2(int fd, struct iovec* iov, int iov_cnt, off_t offset, int flags)
+	// the linux internal call
+	// (https://elixir.bootlin.com/linux/v4.18/source/fs/read_write.c#L1248)
+	// splits the offset argument into a high/low value for compatibility with
+	// 32-bit architectures. The flags argument is the 5th argument.
+
 	fd := kdefs.FD(args[0].Int())
 	addr := args[1].Pointer()
 	iovcnt := int(args[2].Int())
 	offset := args[3].Int64()
-	flags := int(args[4].Int())
-
-	validFlags := linux.RWF_HIPRI
+	flags := int(args[5].Int())
 
 	file := t.FDMap().GetFile(fd)
 	if file == nil {
@@ -219,14 +225,8 @@ func Preadv2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca
 	}
 
 	// Check flags field.
-	if flags != 0 {
-		if flags&^validFlags != 0 {
-			return 0, nil, syserror.EINVAL
-		}
-		// RWF_HIPRI must be called on a file with O_DIRECT flag set.
-		if flags&linux.RWF_HIPRI != 0 && !file.Flags().Direct {
-			return 0, nil, syserror.EINVAL
-		}
+	if flags&^linux.RWF_VALID != 0 {
+		return 0, nil, syserror.EOPNOTSUPP
 	}
 
 	// Read the iovecs that specify the destination of the read.
diff --git a/pkg/sentry/syscalls/linux/sys_write.go b/pkg/sentry/syscalls/linux/sys_write.go
index 08e263112..750a098cd 100644
--- a/pkg/sentry/syscalls/linux/sys_write.go
+++ b/pkg/sentry/syscalls/linux/sys_write.go
@@ -187,6 +187,72 @@ func Pwritev(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca
 	return uintptr(n), nil, handleIOError(t, n != 0, err, kernel.ERESTARTSYS, "pwritev", file)
 }
 
+// Pwritev2 implements linux syscall pwritev2(2).
+// TODO: Implement RWF_HIPRI functionality.
+// TODO: Implement O_SYNC and D_SYNC functionality.
+func Pwritev2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	// While the syscall is
+	// pwritev2(int fd, struct iovec* iov, int iov_cnt, off_t offset, int flags)
+	// the linux internal call
+	// (https://elixir.bootlin.com/linux/v4.18/source/fs/read_write.c#L1354)
+	// splits the offset argument into a high/low value for compatibility with
+	// 32-bit architectures. The flags argument is the 5th argument.
+
+	fd := kdefs.FD(args[0].Int())
+	addr := args[1].Pointer()
+	iovcnt := int(args[2].Int())
+	offset := args[3].Int64()
+	flags := int(args[5].Int())
+
+	if int(args[4].Int())&0x4 == 1 {
+		return 0, nil, syserror.EACCES
+	}
+
+	file := t.FDMap().GetFile(fd)
+	if file == nil {
+		return 0, nil, syserror.EBADF
+	}
+	defer file.DecRef()
+
+	// Check that the offset is legitimate.
+	if offset < -1 {
+		return 0, nil, syserror.EINVAL
+	}
+
+	// Is writing at an offset supported?
+	if offset > -1 && !file.Flags().Pwrite {
+		return 0, nil, syserror.ESPIPE
+	}
+
+	if flags&^linux.RWF_VALID != 0 {
+		return uintptr(flags), nil, syserror.EOPNOTSUPP
+	}
+
+	// Check that the file is writeable.
+	if !file.Flags().Write {
+		return 0, nil, syserror.EBADF
+	}
+
+	// Read the iovecs that specify the source of the write.
+	src, err := t.IovecsIOSequence(addr, iovcnt, usermem.IOOpts{
+		AddressSpaceActive: true,
+	})
+	if err != nil {
+		return 0, nil, err
+	}
+
+	// If pwritev2 is called with an offset of -1, writev is called.
+	if offset == -1 {
+		n, err := writev(t, file, src)
+		t.IOUsage().AccountWriteSyscall(n)
+		return uintptr(n), nil, handleIOError(t, n != 0, err, kernel.ERESTARTSYS, "pwritev2", file)
+	}
+
+	n, err := pwritev(t, file, src, offset)
+	t.IOUsage().AccountWriteSyscall(n)
+	return uintptr(n), nil, handleIOError(t, n != 0, err, kernel.ERESTARTSYS, "pwritev2", file)
+}
+
 func writev(t *kernel.Task, f *fs.File, src usermem.IOSequence) (int64, error) {
 	n, err := f.Writev(t, src)
 	if err != syserror.ErrWouldBlock || f.Flags().NonBlocking {
diff --git a/test/syscalls/BUILD b/test/syscalls/BUILD
index 711b68c76..12c7049e7 100644
--- a/test/syscalls/BUILD
+++ b/test/syscalls/BUILD
@@ -219,6 +219,8 @@ syscall_test(
     test = "//test/syscalls/linux:pty_test",
 )
 
+syscall_test(test = "//test/syscalls/linux:pwritev2_test")
+
 syscall_test(test = "//test/syscalls/linux:pwrite64_test")
 
 syscall_test(test = "//test/syscalls/linux:read_test")
diff --git a/test/syscalls/linux/BUILD b/test/syscalls/linux/BUILD
index aca55f492..f13e32daa 100644
--- a/test/syscalls/linux/BUILD
+++ b/test/syscalls/linux/BUILD
@@ -1338,18 +1338,18 @@ cc_binary(
     name = "preadv2_test",
     testonly = 1,
     srcs = [
+        "file_base.h",
         "preadv2.cc",
-        "readv_common.cc",
-        "readv_common.h",
     ],
     linkstatic = 1,
     deps = [
-        ":file_base",
         "//test/util:file_descriptor",
-        "//test/util:memory_util",
+        "//test/util:posix_error",
         "//test/util:temp_path",
         "//test/util:test_main",
         "//test/util:test_util",
+        "@com_google_absl//absl/memory",
+        "@com_google_absl//absl/strings",
         "@com_google_googletest//:gtest",
     ],
 )
@@ -1453,6 +1453,25 @@ cc_binary(
 )
 
 cc_binary(
+    name = "pwritev2_test",
+    testonly = 1,
+    srcs = [
+        "pwritev2.cc",
+    ],
+    linkstatic = 1,
+    deps = [
+        ":file_base",
+        "//test/util:file_descriptor",
+        "//test/util:posix_error",
+        "//test/util:temp_path",
+        "//test/util:test_main",
+        "//test/util:test_util",
+        "@com_google_absl//absl/strings",
+        "@com_google_googletest//:gtest",
+    ],
+)
+
+cc_binary(
     name = "read_test",
     testonly = 1,
     srcs = ["read.cc"],
diff --git a/test/syscalls/linux/preadv2.cc b/test/syscalls/linux/preadv2.cc
index 642eed624..58a4f9224 100644
--- a/test/syscalls/linux/preadv2.cc
+++ b/test/syscalls/linux/preadv2.cc
@@ -13,23 +13,18 @@
 // limitations under the License.
 
 #include <fcntl.h>
-#include <stdlib.h>
 #include <sys/syscall.h>
 #include <sys/types.h>
 #include <sys/uio.h>
-#include <sys/wait.h>
-#include <unistd.h>
 
-#include <atomic>
 #include <string>
 #include <vector>
 
 #include "gtest/gtest.h"
 #include "gtest/gtest.h"
+#include "absl/memory/memory.h"
 #include "test/syscalls/linux/file_base.h"
-#include "test/syscalls/linux/readv_common.h"
 #include "test/util/file_descriptor.h"
-#include "test/util/memory_util.h"
 #include "test/util/temp_path.h"
 #include "test/util/test_util.h"
 
@@ -60,11 +55,17 @@ std::string SetContent() {
   return content;
 }
 
+ssize_t preadv2(unsigned long fd, const struct iovec* iov, unsigned long iovcnt,
+                off_t offset, unsigned long flags) {
+  // syscall on preadv2 does some weird things (see man syscall and search
+  // preadv2), so we insert a 0 to word align the flags argument on native.
+  return syscall(SYS_preadv2, fd, iov, iovcnt, offset, 0, flags);
+}
+
 // This test is the base case where we call preadv (no offset, no flags).
 TEST(Preadv2Test, TestBaseCall) {
-  if (!IsRunningOnGvisor()) {
-    SKIP_BEFORE_KERNEL(/*major_version=*/4, /*minor_version=*/6);
-  }
+  SKIP_IF(preadv2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
+
   std::string content = SetContent();
 
   const TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
@@ -73,12 +74,13 @@ TEST(Preadv2Test, TestBaseCall) {
       ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDONLY));
 
   std::vector<char> buf(kBufSize);
-  struct iovec iov;
-  iov.iov_base = buf.data();
-  iov.iov_len = buf.size();
+  struct iovec iov[2];
+  iov[0].iov_base = buf.data();
+  iov[0].iov_len = buf.size() / 2;
+  iov[1].iov_base = static_cast<char*>(iov[0].iov_base) + (content.size() / 2);
+  iov[1].iov_len = content.size() / 2;
 
-  EXPECT_THAT(syscall(SYS_preadv2, fd.get(), &iov, /*iov_cnt*/ 1,
-                      /*offset=*/0, /*flags=*/0),
+  EXPECT_THAT(preadv2(fd.get(), iov, /*iovcnt*/ 2, /*offset=*/0, /*flags=*/0),
               SyscallSucceedsWithValue(kBufSize));
 
   EXPECT_EQ(content, std::string(buf.data(), buf.size()));
@@ -86,9 +88,8 @@ TEST(Preadv2Test, TestBaseCall) {
 
 // This test is where we call preadv with an offset and no flags.
 TEST(Preadv2Test, TestValidPositiveOffset) {
-  if (!IsRunningOnGvisor()) {
-    SKIP_BEFORE_KERNEL(/*major_version=*/4, /*minor_version=*/6);
-  }
+  SKIP_IF(preadv2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
+
   std::string content = SetContent();
   const std::string prefix = "0";
 
@@ -102,10 +103,12 @@ TEST(Preadv2Test, TestValidPositiveOffset) {
   iov.iov_base = buf.data();
   iov.iov_len = buf.size();
 
-  EXPECT_THAT(syscall(SYS_preadv2, fd.get(), &iov, /*iov_cnt=*/1,
-                      /*offset=*/prefix.size(), /*flags=*/0),
+  EXPECT_THAT(preadv2(fd.get(), &iov, /*iovcnt=*/1, /*offset=*/prefix.size(),
+                      /*flags=*/0),
               SyscallSucceedsWithValue(kBufSize));
 
+  EXPECT_THAT(lseek(fd.get(), 0, SEEK_CUR), SyscallSucceedsWithValue(0));
+
   EXPECT_EQ(content, std::string(buf.data(), buf.size()));
 }
 
@@ -113,9 +116,8 @@ TEST(Preadv2Test, TestValidPositiveOffset) {
 // read should use the file offset, so the test increments it by one prior to
 // calling preadv2.
 TEST(Preadv2Test, TestNegativeOneOffset) {
-  if (!IsRunningOnGvisor()) {
-    SKIP_BEFORE_KERNEL(/*major_version=*/4, /*minor_version=*/6);
-  }
+  SKIP_IF(preadv2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
+
   std::string content = SetContent();
   const std::string prefix = "231";
 
@@ -123,6 +125,7 @@ TEST(Preadv2Test, TestNegativeOneOffset) {
       GetAbsoluteTestTmpdir(), prefix + content, TempPath::kDefaultFileMode));
   const FileDescriptor fd =
       ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDONLY));
+
   ASSERT_THAT(lseek(fd.get(), prefix.size(), SEEK_SET),
               SyscallSucceedsWithValue(prefix.size()));
 
@@ -131,79 +134,111 @@ TEST(Preadv2Test, TestNegativeOneOffset) {
   iov.iov_base = buf.data();
   iov.iov_len = buf.size();
 
-  EXPECT_THAT(syscall(SYS_preadv2, fd.get(), &iov, /*iov_cnt=*/1,
-                      /*offset=*/static_cast<off_t>(-1), /*flags=*/0),
+  EXPECT_THAT(preadv2(fd.get(), &iov, /*iovcnt=*/1, /*offset=*/-1, /*flags=*/0),
               SyscallSucceedsWithValue(kBufSize));
 
+  EXPECT_THAT(lseek(fd.get(), 0, SEEK_CUR),
+              SyscallSucceedsWithValue(prefix.size() + buf.size()));
+
   EXPECT_EQ(content, std::string(buf.data(), buf.size()));
 }
 
+// preadv2 requires if the RWF_HIPRI flag is passed, the fd must be opened with
+// O_DIRECT. This test implements a correct call with the RWF_HIPRI flag.
+TEST(Preadv2Test, TestCallWithRWF_HIPRI) {
+  SKIP_IF(preadv2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
+
+  std::string content = SetContent();
+
+  const TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
+      GetAbsoluteTestTmpdir(), content, TempPath::kDefaultFileMode));
+  const FileDescriptor fd =
+      ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDONLY));
+
+  EXPECT_THAT(fsync(fd.get()), SyscallSucceeds());
+
+  std::vector<char> buf(kBufSize, '0');
+  struct iovec iov;
+  iov.iov_base = buf.data();
+  iov.iov_len = buf.size();
+
+  EXPECT_THAT(
+      preadv2(fd.get(), &iov, /*iovcnt=*/1, /*offset=*/0, /*flags=*/RWF_HIPRI),
+      SyscallSucceedsWithValue(kBufSize));
+
+  EXPECT_THAT(lseek(fd.get(), 0, SEEK_CUR), SyscallSucceedsWithValue(0));
+
+  EXPECT_EQ(content, std::string(buf.data(), buf.size()));
+}
 // This test calls preadv2 with an invalid flag.
 TEST(Preadv2Test, TestInvalidFlag) {
-  if (!IsRunningOnGvisor()) {
-    SKIP_BEFORE_KERNEL(/*major_version=*/4, /*minor_version=*/6);
-  }
+  SKIP_IF(preadv2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
 
   const TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
       GetAbsoluteTestTmpdir(), "", TempPath::kDefaultFileMode));
   const FileDescriptor fd =
       ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDONLY | O_DIRECT));
 
+  std::vector<char> buf(kBufSize, '0');
   struct iovec iov;
+  iov.iov_base = buf.data();
+  iov.iov_len = buf.size();
 
-  EXPECT_THAT(syscall(SYS_preadv2, fd.get(), &iov, /*iov_cnt=*/1,
-                      /*offset=*/0, /*flags=*/RWF_HIPRI << 1),
-              SyscallFailsWithErrno(EINVAL));
+  EXPECT_THAT(preadv2(fd.get(), &iov, /*iovcnt=*/1,
+                      /*offset=*/0, /*flags=*/0xF0),
+              SyscallFailsWithErrno(EOPNOTSUPP));
 }
 
 // This test calls preadv2 with an invalid offset.
 TEST(Preadv2Test, TestInvalidOffset) {
-  if (!IsRunningOnGvisor()) {
-    SKIP_BEFORE_KERNEL(/*major_version=*/4, /*minor_version=*/6);
-  }
+  SKIP_IF(preadv2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
 
   const TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
       GetAbsoluteTestTmpdir(), "", TempPath::kDefaultFileMode));
   const FileDescriptor fd =
       ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDONLY | O_DIRECT));
-  struct iovec iov;
 
-  EXPECT_THAT(syscall(SYS_preadv2, fd.get(), &iov, /*iov_cnt=*/1,
-                      /*offset=*/static_cast<off_t>(-8), /*flags=*/RWF_HIPRI),
+  auto iov = absl::make_unique<struct iovec[]>(1);
+  iov[0].iov_base = nullptr;
+  iov[0].iov_len = 0;
+
+  EXPECT_THAT(preadv2(fd.get(), iov.get(), /*iovcnt=*/1, /*offset=*/-8,
+                      /*flags=*/RWF_HIPRI),
               SyscallFailsWithErrno(EINVAL));
 }
 
 // This test calls preadv with a file set O_WRONLY.
 TEST(Preadv2Test, TestUnreadableFile) {
-  if (!IsRunningOnGvisor()) {
-    SKIP_BEFORE_KERNEL(/*major_version=*/4, /*minor_version=*/6);
-  }
+  SKIP_IF(preadv2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
 
   const TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
       GetAbsoluteTestTmpdir(), "", TempPath::kDefaultFileMode));
   const FileDescriptor fd =
       ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_WRONLY));
-  struct iovec iov;
 
-  EXPECT_THAT(syscall(SYS_preadv2, fd.get(), &iov, /*iov_cnt=*/1,
+  auto iov = absl::make_unique<struct iovec[]>(1);
+  iov[0].iov_base = nullptr;
+  iov[0].iov_len = 0;
+
+  EXPECT_THAT(preadv2(fd.get(), iov.get(), /*iovcnt=*/1,
                       /*offset=*/0, /*flags=*/0),
               SyscallFailsWithErrno(EBADF));
 }
 
 // Calling preadv2 with a non-negative offset calls preadv.  Calling preadv with
 // an unseekable file is not allowed. A pipe is used for an unseekable file.
-TEST(Preadv2Test, TestUnseekableFile) {
-  if (!IsRunningOnGvisor()) {
-    SKIP_BEFORE_KERNEL(/*major_version=*/4, /*minor_version=*/6);
-  }
+TEST(Preadv2Test, TestUnseekableFileInvalid) {
+  SKIP_IF(preadv2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
 
   int pipe_fds[2];
 
   ASSERT_THAT(pipe(pipe_fds), SyscallSucceeds());
 
-  struct iovec iov;
+  auto iov = absl::make_unique<struct iovec[]>(1);
+  iov[0].iov_base = nullptr;
+  iov[0].iov_len = 0;
 
-  EXPECT_THAT(syscall(SYS_preadv2, pipe_fds[0], &iov, /*iov_cnt=*/1,
+  EXPECT_THAT(preadv2(pipe_fds[0], iov.get(), /*iovcnt=*/1,
                       /*offset=*/2, /*flags=*/0),
               SyscallFailsWithErrno(ESPIPE));
 
@@ -211,6 +246,33 @@ TEST(Preadv2Test, TestUnseekableFile) {
   EXPECT_THAT(close(pipe_fds[1]), SyscallSucceeds());
 }
 
+TEST(Preadv2Test, TestUnseekableFileValid) {
+  SKIP_IF(preadv2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
+
+  int pipe_fds[2];
+
+  ASSERT_THAT(pipe(pipe_fds), SyscallSucceeds());
+
+  std::vector<char> content(32, 'X');
+
+  EXPECT_THAT(write(pipe_fds[1], content.data(), content.size()),
+              SyscallSucceedsWithValue(content.size()));
+
+  std::vector<char> buf(content.size());
+  auto iov = absl::make_unique<struct iovec[]>(1);
+  iov[0].iov_base = buf.data();
+  iov[0].iov_len = buf.size();
+
+  EXPECT_THAT(preadv2(pipe_fds[0], iov.get(), /*iovcnt=*/1,
+                      /*offset=*/static_cast<off_t>(-1), /*flags=*/0),
+              SyscallSucceedsWithValue(buf.size()));
+
+  EXPECT_EQ(content, buf);
+
+  EXPECT_THAT(close(pipe_fds[0]), SyscallSucceeds());
+  EXPECT_THAT(close(pipe_fds[1]), SyscallSucceeds());
+}
+
 }  // namespace
 
 }  // namespace testing
diff --git a/test/syscalls/linux/pwritev2.cc b/test/syscalls/linux/pwritev2.cc
new file mode 100644
index 000000000..a6949f08e
--- /dev/null
+++ b/test/syscalls/linux/pwritev2.cc
@@ -0,0 +1,337 @@
+// Copyright 2018 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <fcntl.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "gtest/gtest.h"
+#include "test/syscalls/linux/file_base.h"
+#include "test/util/file_descriptor.h"
+#include "test/util/temp_path.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+#ifndef SYS_pwritev2
+#if defined(__x86_64__)
+#define SYS_pwritev2 328
+#else
+#error "Unknown architecture"
+#endif
+#endif  // SYS_pwrite2
+
+#ifndef RWF_HIPRI
+#define RWF_HIPRI 0x1
+#endif  // RWF_HIPRI
+
+#ifndef RWF_DSYNC
+#define RWF_DSYNC 0x2
+#endif  // RWF_DSYNC
+
+#ifndef RWF_SYNC
+#define RWF_SYNC 0x4
+#endif  // RWF_SYNC
+
+constexpr int kBufSize = 1024;
+
+void SetContent(std::vector<char>& content) {
+  for (uint i = 0; i < content.size(); i++) {
+    content[i] = static_cast<char>((i % 10) + '0');
+  }
+}
+
+ssize_t pwritev2(unsigned long fd, const struct iovec* iov,
+                 unsigned long iovcnt, off_t offset, unsigned long flags) {
+  // syscall on pwritev2 does some weird things (see man syscall and search
+  // pwritev2), so we insert a 0 to word align the flags argument on native.
+  return syscall(SYS_pwritev2, fd, iov, iovcnt, offset, 0, flags);
+}
+
+// This test is the base case where we call pwritev (no offset, no flags).
+TEST(Writev2Test, TestBaseCall) {
+  SKIP_IF(pwritev2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
+
+  const TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
+      GetAbsoluteTestTmpdir(), "", TempPath::kDefaultFileMode));
+  const FileDescriptor fd =
+      ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR));
+
+  std::vector<char> content(kBufSize);
+  SetContent(content);
+  struct iovec iov[2];
+  iov[0].iov_base = content.data();
+  iov[0].iov_len = content.size() / 2;
+  iov[1].iov_base = static_cast<char*>(iov[0].iov_base) + (content.size() / 2);
+  iov[1].iov_len = content.size() / 2;
+
+  ASSERT_THAT(pwritev2(fd.get(), iov, /*iovcnt=*/2,
+                       /*offset=*/0, /*flags=*/0),
+              SyscallSucceedsWithValue(kBufSize));
+
+  std::vector<char> buf(kBufSize);
+  EXPECT_THAT(read(fd.get(), buf.data(), kBufSize),
+              SyscallSucceedsWithValue(kBufSize));
+
+  EXPECT_EQ(content, buf);
+}
+
+// This test is where we call pwritev2 with a positive offset and no flags.
+TEST(Pwritev2Test, TestValidPositiveOffset) {
+  SKIP_IF(pwritev2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
+
+  std::string prefix(kBufSize, '0');
+
+  const TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
+      GetAbsoluteTestTmpdir(), prefix, TempPath::kDefaultFileMode));
+  const FileDescriptor fd =
+      ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR));
+
+  std::vector<char> content(kBufSize);
+  SetContent(content);
+  struct iovec iov;
+  iov.iov_base = content.data();
+  iov.iov_len = content.size();
+
+  ASSERT_THAT(pwritev2(fd.get(), &iov, /*iovcnt=*/1,
+                       /*offset=*/prefix.size(), /*flags=*/0),
+              SyscallSucceedsWithValue(content.size()));
+
+  std::vector<char> buf(prefix.size() + content.size());
+  EXPECT_THAT(read(fd.get(), buf.data(), buf.size()),
+              SyscallSucceedsWithValue(buf.size()));
+
+  std::vector<char> want(prefix.begin(), prefix.end());
+  want.insert(want.end(), content.begin(), content.end());
+  EXPECT_EQ(want, buf);
+}
+
+// This test is the base case where we call writev by using -1 as the offset.
+// The write should use the file offset, so the test increments the file offset
+// prior to call pwritev2.
+TEST(Pwritev2Test, TestNegativeOneOffset) {
+  SKIP_IF(pwritev2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
+
+  const std::string prefix = "00";
+  const TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
+      GetAbsoluteTestTmpdir(), prefix.data(), TempPath::kDefaultFileMode));
+  const FileDescriptor fd =
+      ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR));
+  ASSERT_THAT(lseek(fd.get(), prefix.size(), SEEK_SET),
+              SyscallSucceedsWithValue(prefix.size()));
+
+  std::vector<char> content(kBufSize);
+  SetContent(content);
+  struct iovec iov;
+  iov.iov_base = content.data();
+  iov.iov_len = content.size();
+
+  ASSERT_THAT(pwritev2(fd.get(), &iov, /*iovcnt*/ 1,
+                       /*offset=*/static_cast<off_t>(-1), /*flags=*/0),
+              SyscallSucceedsWithValue(content.size()));
+
+  ASSERT_THAT(lseek(fd.get(), 0, SEEK_CUR),
+              SyscallSucceedsWithValue(prefix.size() + content.size()));
+
+  std::vector<char> buf(prefix.size() + content.size());
+  EXPECT_THAT(pread(fd.get(), buf.data(), buf.size(), /*offset=*/0),
+              SyscallSucceedsWithValue(buf.size()));
+
+  std::vector<char> want(prefix.begin(), prefix.end());
+  want.insert(want.end(), content.begin(), content.end());
+  EXPECT_EQ(want, buf);
+}
+
+// pwritev2 requires if the RWF_HIPRI flag is passed, the fd must be opened with
+// O_DIRECT. This test implements a correct call with the RWF_HIPRI flag.
+TEST(Pwritev2Test, TestCallWithRWF_HIPRI) {
+  SKIP_IF(pwritev2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
+
+  const TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
+      GetAbsoluteTestTmpdir(), "", TempPath::kDefaultFileMode));
+  const FileDescriptor fd =
+      ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR));
+
+  std::vector<char> content(kBufSize);
+  SetContent(content);
+  struct iovec iov;
+  iov.iov_base = content.data();
+  iov.iov_len = content.size();
+
+  EXPECT_THAT(pwritev2(fd.get(), &iov, /*iovcnt=*/1,
+                       /*offset=*/0, /*flags=*/RWF_HIPRI),
+              SyscallSucceedsWithValue(kBufSize));
+
+  std::vector<char> buf(content.size());
+  EXPECT_THAT(read(fd.get(), buf.data(), buf.size()),
+              SyscallSucceedsWithValue(buf.size()));
+
+  EXPECT_EQ(buf, content);
+}
+
+// This test checks that pwritev2 can be called with valid flags
+TEST(Pwritev2Test, TestCallWithValidFlags) {
+  SKIP_IF(pwritev2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
+
+  const TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
+      GetAbsoluteTestTmpdir(), "", TempPath::kDefaultFileMode));
+  const FileDescriptor fd =
+      ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR));
+
+  std::vector<char> content(kBufSize, '0');
+  struct iovec iov;
+  iov.iov_base = content.data();
+  iov.iov_len = content.size();
+
+  EXPECT_THAT(pwritev2(fd.get(), &iov, /*iovcnt=*/1,
+                       /*offset=*/0, /*flags=*/RWF_DSYNC),
+              SyscallSucceedsWithValue(kBufSize));
+
+  std::vector<char> buf(content.size());
+  EXPECT_THAT(read(fd.get(), buf.data(), buf.size()),
+              SyscallSucceedsWithValue(buf.size()));
+
+  EXPECT_EQ(buf, content);
+
+  SetContent(content);
+
+  EXPECT_THAT(pwritev2(fd.get(), &iov, /*iovcnt=*/1,
+                       /*offset=*/0, /*flags=*/0x4),
+              SyscallSucceedsWithValue(kBufSize));
+
+  ASSERT_THAT(lseek(fd.get(), 0, SEEK_CUR),
+              SyscallSucceedsWithValue(content.size()));
+
+  EXPECT_THAT(pread(fd.get(), buf.data(), buf.size(), /*offset=*/0),
+              SyscallSucceedsWithValue(buf.size()));
+
+  EXPECT_EQ(buf, content);
+}
+
+// This test calls pwritev2 with a bad file descriptor.
+TEST(Writev2Test, TestBadFile) {
+  SKIP_IF(pwritev2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
+  ASSERT_THAT(pwritev2(/*fd=*/-1, /*iov=*/nullptr, /*iovcnt=*/0,
+                       /*offset=*/0, /*flags=*/0),
+              SyscallFailsWithErrno(EBADF));
+}
+
+// This test calls pwrite2 with an invalid offset.
+TEST(Pwritev2Test, TestInvalidOffset) {
+  SKIP_IF(pwritev2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
+
+  const TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
+      GetAbsoluteTestTmpdir(), "", TempPath::kDefaultFileMode));
+  const FileDescriptor fd =
+      ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR));
+
+  struct iovec iov;
+  iov.iov_base = nullptr;
+
+  EXPECT_THAT(pwritev2(fd.get(), &iov, /*iovcnt=*/1,
+                       /*offset=*/static_cast<off_t>(-8), /*flags=*/0),
+              SyscallFailsWithErrno(EINVAL));
+}
+
+TEST(Pwritev2Test, TestUnseekableFileValid) {
+  SKIP_IF(pwritev2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
+
+  int pipe_fds[2];
+
+  ASSERT_THAT(pipe(pipe_fds), SyscallSucceeds());
+
+  std::vector<char> content(32, '0');
+  SetContent(content);
+  struct iovec iov;
+  iov.iov_base = content.data();
+  iov.iov_len = content.size();
+
+  EXPECT_THAT(pwritev2(pipe_fds[1], &iov, /*iovcnt=*/1,
+                       /*offset=*/static_cast<off_t>(-1), /*flags=*/0),
+              SyscallSucceedsWithValue(content.size()));
+
+  std::vector<char> buf(content.size());
+  EXPECT_THAT(read(pipe_fds[0], buf.data(), buf.size()),
+              SyscallSucceedsWithValue(buf.size()));
+
+  EXPECT_EQ(content, buf);
+
+  EXPECT_THAT(close(pipe_fds[0]), SyscallSucceeds());
+  EXPECT_THAT(close(pipe_fds[1]), SyscallSucceeds());
+}
+
+// Calling pwritev2 with a non-negative offset calls pwritev.  Calling pwritev
+// with an unseekable file is not allowed. A pipe is used for an unseekable
+// file.
+TEST(Pwritev2Test, TestUnseekableFileInValid) {
+  SKIP_IF(pwritev2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
+
+  int pipe_fds[2];
+  struct iovec iov;
+  iov.iov_base = nullptr;
+
+  ASSERT_THAT(pipe(pipe_fds), SyscallSucceeds());
+
+  EXPECT_THAT(pwritev2(pipe_fds[1], &iov, /*iovcnt=*/1,
+                       /*offset=*/2, /*flags=*/0),
+              SyscallFailsWithErrno(ESPIPE));
+
+  EXPECT_THAT(close(pipe_fds[0]), SyscallSucceeds());
+  EXPECT_THAT(close(pipe_fds[1]), SyscallSucceeds());
+}
+
+TEST(Pwritev2Test, TestReadOnlyFile) {
+  SKIP_IF(pwritev2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
+
+  const TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
+      GetAbsoluteTestTmpdir(), "", TempPath::kDefaultFileMode));
+  const FileDescriptor fd =
+      ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDONLY));
+
+  struct iovec iov;
+  iov.iov_base = nullptr;
+
+  EXPECT_THAT(pwritev2(fd.get(), &iov, /*iovcnt=*/1,
+                       /*offset=*/0, /*flags=*/0),
+              SyscallFailsWithErrno(EBADF));
+}
+
+// This test calls pwritev2 with an invalid flag.
+TEST(Pwritev2Test, TestInvalidFlag) {
+  SKIP_IF(pwritev2(-1, nullptr, 0, 0, 0) < 0 && errno == ENOSYS);
+
+  const TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
+      GetAbsoluteTestTmpdir(), "", TempPath::kDefaultFileMode));
+  const FileDescriptor fd =
+      ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR | O_DIRECT));
+
+  struct iovec iov;
+  iov.iov_base = nullptr;
+
+  EXPECT_THAT(pwritev2(fd.get(), &iov, /*iovcnt=*/1,
+                       /*offset=*/0, /*flags=*/0xF0),
+              SyscallFailsWithErrno(EOPNOTSUPP));
+}
+
+}  // namespace
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/util/test_util.h b/test/util/test_util.h
index 2a7609e5c..cd71fdd64 100644
--- a/test/util/test_util.h
+++ b/test/util/test_util.h
@@ -217,13 +217,6 @@ void TestInit(int* argc, char*** argv);
     }                                                                        \
   } while (0)
 
-#define SKIP_BEFORE_KERNEL(maj, min)                              \
-  do {                                                            \
-    auto version = ASSERT_NO_ERRNO_AND_VALUE(GetKernelVersion()); \
-    SKIP_IF(version.major < (maj) ||                              \
-            (version.major == (maj) && version.minor < (min)));   \
-  } while (0)
-
 enum class Platform {
   kNative,
   kKVM,